Beta-phenyl-beta-hydrocarbon-hydracrylic acid-2-nu, nu-diethylamine ethyl esters



United States Patent 7 O 3,144,464 p PHENYL ,8 HYDROCARBON HYDRACRYLIC ACID-2-N,N-DIETHYLAMINE ETHYL ESTERS Hartmund Wollweber and Rudolf Hiltmann, Wuppertal- Elberfeld, Georg Kimmerle, Blankenstein (Ruhr), and Horst Kreiskott, Wuppertal-Elberfeld, Germany, assignors to Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Filed Feb. 25, 1960, Ser. No. 10,866 Claims priority, application Germany Feb. 27, 1959 4 Claims. (Cl. 260-3405) This invention relates to, and has as its object, the production of novel basic substituted esters of hydracrylic acid and, more specifically, to basic substituted esters of [3-substituted hydracrylic acid, which have been found to constitute therapeutically useful compounds and which are particularly effective in the treatment of Parkinsons disease.

It has already carboxylic acids can be obtained by reacting the free acids or the functional acid derivatives thereof with amino alcohols or their derivatives, which react with the acids and acid derivatives with ester formation.

It has now been discovered that therapeutically valuable compounds, which are relatively non-toxic and which have a marked and sustained anti-tremorin activity and are particularly effective in the treatment of Parkinsons disease, can be obtained if the carboxylic acids used in the esterification reaction are fl-substituted hydracrylic acids of the following general formula or their functional derivatives:

in which R represents hydrogen or an acyl radical and R represents a saturated or unsaturated bicyclo-(2,2,1) heptyl radical, nortricyclyl-, isopropy1-, isopropenylor the tertiary butyl radical. The phenyl core can be substituted, if necessary, with one or more alkoxy-, methylenedioxyor mercapto-groups and preferably is one of the following: phenyl, alkoxyphenyl, methylene dioxyphenyl and alkylrnercaptophenyl. In the esterification reaction of the carboxylic acid or its functional derivabeen established that basic esters of tive with the amino alcohol or its functional derivative,

novel compounds are obtained, which possess the general formula Ra OHz-COOX-N in which R and R are as defined above, X is a straight or branched chain alkylene group, R and R each represent an alkyl radical, and R and R may be joined with one another or one of R and R with a carbon atom of X to form a heterocyclic N-containing ring which may also be substituted as for example a piperidino, piperazino, pyrrolidino or morpholino ring. 1

The novel basic substituted esters of fl-substituted hydracrylic acid can be prepared in the known manner by reacting the free carboxylic acid or its functional derivative with an amino alcohol. The reaction may be effected, employing inert solvents and diluents and preferably is carried out at an elevated temperature. It has been found advantageous to carry out the reaction in the presence of a hydrogen-halide binding agent, such as for example basic alcoholate.

Alternatively, the fl-substituted hydracrylic acid esters can be inter-esterified with amino alcohols. This inter- 3,144,464 Patented, Aug. 1 1,, 1964 esterification reaction is carried out by reacting a fl-substituted hydracrylic acid ester and an amino alcohol in the presence of a basic catalyst, as for example an alkali metal, preferably in the additional presence of a solvent, as for example toluene or xylene, at a temperature of up to 150 C. The inter-esterification may, if necessary, be effected at a reduced pressure. Subsequently, the hydroxyl group can be acylated at normal or at an elevated temperature with a carboxylic acid anhydride or carboxylic acid chloride. The compounds obtained in this way can be decomposed into their optically active components.

Inasmuch as the compounds obtained according to the processes described above are unsaturated, the corresponding saturated compounds can be obtained by hydrogenation.

Salts, like citrates, succinates, acetates, lactates, bitartrates, naphthalene disulfonates, hydrochlorides, hydro bromides, hydroiodides, nitrates, sulfates etc., can easily be produced by reacting the free basic esters with the corresponding acids in a solvent. Generally, the salt separates after the reaction; otherwise, the solvent must be removed leaving behind the salt.

Basic B-diphenyl hydracrylic acid esters have already been described (Ann. Rept. Tohuku Coll. Pharm No. 2 (1955), 42-49; Journ. Am. Chem. Soc. 65 (1943), 1967), which have a moderately analgesic, mydn'atic and local anesthetic effect. By the substitution of a bicyclo- (2,2,1)-heptenyl-, nortricyclyL, isopropylor tertiary butyl radical in place of the phenyl group, compounds are obtained which, in comparison with the described fi-diphenylhydracrylic acid esters, possess an entirely different pharmacological elfect.

The compounds have demonstrated in experimental studies a strong anti-Parkinson effect, which for example the known diphenyl hydracrylic acid esters completely lack. A comparison of the therapeutic indices makes this particularly clear.

The better toleration of the known compounds, as compared to the previously known compounds, and the effectiveness of the compounds as anti-tremorin agents has been demonstrated by quantitative data on acute toxicity and pharmacological determinations. v

The following table contains a compilation of results of animal experiments. For testing the anti-Parkinson effect, a modification of the experiment of Everett (Science 177 (1956), page 1238) was employed: White mice, brought into water of 37 C., keep swimming for a long time, in any case more than 8 hours. If, however, Tremorin is injected in a dose of 25 mg./kg. of mouse intravenously, they drown regularly inside 30 minutes. This affords the possibility to test antagonists of Tremorin whether they can prevent death by drowning. For the test, each time a group of 10 mice was used, and the substance tested as a Tremorin antagonist was likewise injected intravenously immediately following the Tremorin injection. The active substances were further tested for their toxicity by intravenous injection in the mice. As a measure of the activity, the therapeutic index can be calculated therefrom, as the proportion of the LD to the ED i.e., the dose which saves saves 50% of the animals intoxicated with 'Trernorin.

The starting @fi-disubstituted hydracrylic acid ester used in accordance with the invention can be obtained with various known methods, as for example by reaction of a corresponding ketone with bromacetic acid ester according to Reformatsky. The carboxylic acids are obtained as a result of saponification. By this process, for example, the following compounds can be produced:

fl-Phenyl-B- (2-bicyclo[2,2, 1 -heptene- 5 -yl) -hydracrylic acid, M.P. 124 126" 0; ethyl ester B.P. C.

3 fl-Phenyl-fi-(2-nortricyclyl)-hydracrylic acid ethyl ester,

B.P. 140 C. fi-Phenyl-B-isopropyl-hydracrylic acid, M.P. 118-119" C.;

ethyl ester B.P. l08110 C.

4 Example] 40 g. fl-phenyl-fl-(2-bicyclo-[2,2,1]-heptene-(5)-yl)-hydracrylic acid ethyl ester is heated with 38 g. 2-N,N-diethylaminoethanol and 0.5 g. sodium in an oil bath at a fl'phenyl'fi'isopropenyl'hydracrxfic acid 124-125 a temperature of from 1 10120 C. until cc. of a Vigreux C-ethy1esterB-P'1-5114-1180 44150 column of ethanol are liberated by the reaction. The ls'phenyl'fi'tertbutyl'hydrfcryhc acld M excess diethylaminoethanol is distilled in vacuum. The residue is dissolved in dilute hydrochloric acid, Washed p-( -lti[ th henyl)-p-1sopropyl-hydracryl1c acld, M-P- with ether and made alkaline with a potash solution. 10 The separated oil is dissolved in ether and, after being fl-( -Ethoxyphenyl)-p-1sopropyl-hydracryl1c acid, M.P. dried over potash, is subjected to vacuum distillation. 9 The yield is 33 grams B-phenyl-fi-(2-bicyclo-[2,2,1]-hepfi-( A- yp y )-fiand, tene-(5)-yl)-hydracrylic acid-2,N,N-diethylamino ethyl M.P. l131l4 C. ester having B.P. 180-184 C. The citrate is pro- 5-(3,4 methylenedioxyphenyl)-,B-isopropyl hy ra ryli 15 duced from the ester by the addition of a mol citric acid acid, M.P. 133-134 C. in an isopropanol solution. M.P. 86-87 C.

TABLE EDso, LDso, Therag., g.lkg., peutic mouse, mouse, index LV. LV,

(a) Known compound: Q OH O/ 2 s \CH2CO0CH2CH2N\ 40 (b) Compounds in accordance with the invention:

\O C1115 CH -C 0 o CHIGHzN 5. 0 25 citrate Q O z s \CH:C O O CHzCHzN 1. 4 100 71 citrate C/ 02 5 (CH3)3C CHT-GOOCHZCHiN 3.0 50

CzHs

citrate /0H C\ 0.75 87.5 115 (CHQzC CHz-COOOHgCHzN citrate The following examples are given by way of illustration and not limitation:

In analogous fashion, the fl-phenyl-B-(-2-nortricyclyl)- hydracrylic acid-2-N,N-diethylaminoethyl ester, B.P.

. 5 C., citrate M.P. 9293 C., is obtained from fi-phenyl-fi- (2-nortricyclyl)-hydracrylic acid ester and 2-N,N-diethylaminoethanol.

Example 2 22.2 g. fl-phenyl-B-tert. butyl-hydracrylic acid is added to a solution of 2.3 g. sodium in 100 cc. isopropanol. 18 g. 2-N,N-diethylaminoethylchloride-hydrochloride is illtroduced and the mixture heated under reflux for 6 hours. The solvent is distilled ed in vacuum. The residue is dissolved in dilute hydrochloric acid and the unsubstituted initial material washed in ether. The hydrochloric acid phase is made alkaline. The oil, separated out after being extracted with ether, is subjected to distillation. The yield is 22 g. B-phenyl-fl-tert.-butylhydracrylic acid-2- N,N-diethylaminoethyl ester having a B.P. l46148 C. Citrate M.P. 10l102 C.

Example 3 15 g. fi-phenyl-fi-isopropyl-hydracrylic acid is heated overnight under reflux with 13 g. 3-N-pyrrolidinopropylchloride in 100 cc. of isopropanol. After the hot solution has been fitered, the solvent is distilled ofl in a vacuum. The residue is dissolved in ether, and the base is liberated through the addition of potash. From the ether solution, after drying over potassium carbonate and distilling off of the solvent, B-phenyl-,B-isopropyl-hydracrylic acid-3-N- pyrrolidinopropyl ester with B.P. 158162 is obtained in a mixture of almost colorless oil. To change to the citrate, an alcohol solution of the ester with the calculated mixture of citric acid (1 mol) is added. On cooling, the citrate separates out into colorless crystals.

In analogous manner, the following esters can be obtained by reaction of corresponding ,B-disubstituted hydracrylic acids and the corresponding aminoalkylhalides:

g Phenyl B-isopropyl-hydracrylic acid-3-N,N-dimethylarninopropyl ester, B.P. 140 C.; citrate M.P. 63-65 C.

,B Phenyl B-isopropyl-hydracrylic acid-2-N,N-dimethylaminopropyl ester, B.P. 134 C.; hydrochloride M.P. 104l05 C.

,8 Phenyl fi-isopropyl-hydracrylic acid-2-N,N-dimethylaminoethyl ester, B.P. 128 C.; citrate M.P. 74- 75 C.

[3 Phenyl [i-isopropyl-hydracrylic acid-Z-N-pyrrolidinoisopropyl ester, B.P. 162 C.; citrate M.P. 7880 C.

,8 Phenyl-B-isopropyl-hydracrylic acid-Z-N-pyrrolidinoethylester, B.P. 158 C.; citrate M.P. 7576 C.

[3 Phenyl isopropyl-hydracrylic acid-3-N,N-diethylaminopropyl ester, B.P. 164 C.; citrate M.P. 77- 78 C.

B Phenyl 3 isopropyl-hydracrylic acid-2,N,N-diethyl aminoethyl ester, B.P. 144 C.; citrate M.P. 770 C.

,8 Phenyl-B-isopropyl-hydracrylic acid-2-(2-piperindine- N-methyl) ethyl ester, B.P. 180 C.

l? Phenyl 5 isopropyl hydracrylic acid N methylpiperidyl-(3)-ester, B.P. 170 C.; hydrochloride M.P. 124-126 C.

,B-Phenyl-B-isopropyl-hydracrylic acid 2,N,N-dimethyl- 6 amino-2,2-dimethylethyl ester, B.P. 128 C.; hydrochloride M.P. 9899 C. fl-Phenyl-B-isopropenyl-hydracrylic acid-2,N,N-dirnethylaminoethyl ester, B.P. 154156 C.; hydrochloride M.P. 99 C.

fl-(p-Methoxyphenyl) -B-isopropyl-hydracrylic acid 2-N- pyrrolidinoethyl ester, B.P. 185 C.; citrate M.P. 6970 C.

fi-(p-Methoxyphenyl) -B-isopropyl-hydracrylic acid-2-N,N diethylaminoethyl ester, B.P. 175 C.; citrate M.P. 87 C.

B-(3,4-dirnethoxyphenyl)-B-isopropyl-hydracrylic acid-2- N,N-diethylaminoethyl ester, B.P. 190 C.; citrate M.P. 98-99 C.

{3 (3,4 'nethylenedioxyphenyl)fl-isopropyl-hydracrylic acid-2-N,N-diethylaminoethyl ester, B.P. l86188 C.; citrate M.P. 5455 C.

fi-(p-Ethoxyphenyl)-fl-isopropyl-hydracrylic acid-2-N,N- diethylaminoethyl ester, B.P. 180 C.; citrate M.P. 89 C.

Example 4 22.2 g. ,B-phenyl-fl-isopropyl-hydracrylic acid is heated overnight in a reflux with cc, of isopropanol with 14.7 g. 2-N-piperidino-ethylchloride. The solution is filtered hot, reduced to 45 cc. and Washed with ether. The yield is 30 g. B-phenyl- 8-isopropyl-hydracrylic acid-2-N-piperidinoethyl ester hydrochloride, M.P. 122l23 C. In the same way, fl-phenyl-/3-isopropyl-hydracrylic acid-Z-N- morpholinoethyl ester hydrochloride, M.P. l25l26 C. is obtained from B-phenyl-fi-isopropyl-hydracrylic acid and Z-N-morpholinoethyl ester hydrochloride.

The new compounds or their salts may find application as drugs in the form of pharmaceutical preparations, which contain them in mixtures With organic or inorganic, solid or liquid vehicles, adapted to oral or parenteral administration, possibly With other pharmaceutical agents added.

We claim:

1. fl-Phenyl-B-tert. butyl-hydracrylic acid-2,N,N-diethylaminoethyl ester.

2. B Phenyl 5 isopropyl-hydracrylic acid-2-N,N-diethylaminoethyl este 3. fl-(p-Methoxyphenyl)-B-is0propyl-hydracrylic acid- 2-N,N-diethylamino ethyl ester.

4. 5 (3,4 -methylenedioxyphenyl)-B-isopropyl-hydracrylic acid-2-N,N-diethylaminoethyl ester.

References Cited in the file of this patent UNITED STATES PATENTS 2,872,374 Beiler et al. Feb. 3, 1959 2,884,426 Kottler et a1 Apr. 28, 1959 2,922,744 Mills et al Jan. 26, 1960 2,922,795 Blicke Jan. 26, 1960 2,987,517 Martin et a1. June 6, 1961 OTHER REFERENCES Blicke et al.: I. Am. Chem. Soc., vol. 65, pp. 1967- 1970 (1943).

Breusch et al.: Chemical Abstracts, vol. 49, page 10,885 (1955). 

4. B-(3,4 - METHYLENEDIOXYPHENYL) - B - ISOPROPYL-HYDRACRYLIC ACID-2-N,N-DIETHYLAMINOETHYL ESTER. 